I recently picked up a car with some nice wheels. However, the wheels required a mallet to get them off. This usually suggests that the wheels are corroded on to the hub. However, once off, no corrosion was visible. There was some form of grease around the centre of the hub. This makes me think that the centre bore of the wheel is just too small for the hub and the previous owner used grease to get them on and off easier (didn't help!). As the difference in being too snug and fitting freely must be really marginal (maybe 1mm), would I be able to just sand out the middle of the wheel centre with some fine grit, and then repaint? I have seen people say that you can get the hole widened with a lathe, but that is usually when the difference is in excess of 5mm or so. Obviously one concern is that it could cause a weight imbalance doing it by hand. Again, is this marginal due to the small amount of material that needs to be removed? My other thought is that, because the material that needs to be removed is so close to the rotational centre of the wheel, the effect of material loss here would be less than that of the material lost when kerbing the outside of the wheel. Thoughts? Concerns?